Ophthalmology Flashcards
What is glaucoma?
Optic nerve damage from rise in intraocular pressure
Glaucoma pathophysiology? Normal IOP value?
- Imbalance in aqueous humour production / drainage - usually blockage
- normal pressure 10-21 mmHg
What is the pathophysiology of open angle glaucoma?
a gradual increase in resistance within the trabecular network results in increased IOP and damage to optic nerve
open angle glaucoma RF?
- increased age
- myopia (near sighted)
- FHx
- black ethnic background
Open angle glaucoma Px?
typically asymptomatic
if symptomatic:
- tunnel vision
- halos around lights
- pain
- headaches
Open angle glaucoma screening
- strong FHx - every 2yrs from 30yo
- every 5yrs >40yo, every 2yrs >60
Open angle glaucoma Ix ?
- visual fields - tunnel vision
- fundoscopy / slit lamp - cupping of optic disc
- Goldmann applanation tonometry - checks intraocular pressure
NB can use non-contact tonometry
- puff of air, estimate IOP (raised)
Open angle glaucoma Mx?
Start when IOP >24 mmHg:
- 360-degree selective laser trabeculoplasty - involves directing a laser at trabecular network to try and improve drainage
1st line medical Tx:
- prostaglandin analogue eye drops e.g latanoprost
other topical options?
- beta blockers e.g. timolol
- carbonic anhydrase inhibitor e.g. acetazolamide
- alpha 2 agonists e.g. brimonidine
surgical option?
- trabeculectomy
What is acute angle closure glaucoma?
- complete closure of angle between the iris and cornea (e.g. due to iris bulging forward) which prevents drainage of the aqueous fluid leading to IOP and optic nerve damage
ophthalmic emergency!!!
Risk factors for acute angle closure glaucoma?
- Increasing age
- Family history
- Female (four times more likely than males)
- Chinese and East Asian ethnic origin
- Shallow anterior chamber
- hyperopia
contributory medications? TCAs, adrenergic meds and anticholinergic meds
AACG Px
- red, painful eye
- N+V
- headache
- halo around lights
- sx worse with pupil dilatation - eg will be watching TV in dark room
AACG examination findings?
- pupil sluggish + dilated
- eye hard to palpation
- reduced visual acuity
- hazy cornea (oedema)
AACG Ix
- tonometry - IOP >60
- gonioscopy - look at angle (lens on slit lamp)
AACG Mx
- lie on back w/o pillow, urgent ophthal referral
- Pilocarpine eye drops (2% for blue and 4% for brown eyes) = acts on muscarinic receptors around iris to prompt pupil constriction + ciliary muscle constriction to try and open up path for aqueous humour flow
- Acetazolamide 500 mg orally = reduces aqueous humour production
- analgesia +/- antiemetics
definitive treatment = laser iridotomy - both eyes
what is age related macular degeneration? what are the two types of ARMD?
damage to the macula with central vision loss
- most common cause of blindness in
UK
- Wet (also called neovascular), accounting for 10% of cases
- Dry (also called non-neovascular), accounting for 90% of cases
ARMD - risk factors?
Older age
Smoking
Family history
Cardiovascular disease (e.g., hypertension)
Obesity
Poor diet (low in vitamins and high in fat)
ARMD pathophysiology?
- Degeneration of retinal photoreceptors
- formation of drusen (protein and lipid deposits)
- atrophy of retinal pigment epithelium
Dry / atrophic - 90% - early
Drusen, changes in pigmentation of retinal pigment endothelium
Wet / exudative - 10% - late
choroidal neovascularisation, VEGF, oedema, rapid vision loss
ARMD Px?
- Gradual loss of central vision
- Reduced visual acuity
- Crooked or wavy appearance to straight lines (metamorphopsia)
ARMD Ix
- visual acuity: reduced
- fundoscopy: drusen, red patches in wet ARMD
- Amsler grid testing - line appears crooked
- Slit lamp - pigmentary/exudative/haemorrhagic changes
- fluorescein angiography to see neovascularisation and leakage
- optical coherence tomography (OCT) to confirm Dx and monitor
ARMD Mx
Urgent referral to ophthalmology
Dry ARMD?
- stop smoking, control BP
- zinc, vit A, C, E
Wet ARMD?
- intravitreal injection of Anti-VEGF
Diabetic retinopathy
Retinal deterioration from blood vessel damage due to high blood sugar levels
how do you classify diabetic retinopathy?
Proliferative – neovascularisation and vitreous haemorrhage
Non proliferative - micro aneurysms, retinal haemorrhages, hard exudates, blot haemorrhages
NB maculopathy exists separately and involves exudates in macula and macula oedema
Diabetic retinopathy Px
non proliferative? asymptomatic
proliferative? vitreous haemorrhage, floaters, blurred vision
Diabetic retinopathy Ix
- visual acuity
- fundoscopy
- fluroscein angiography
Diabetic retinopathy Mx
- optimise BMs, BP, lipids, healthy diet, stop smoking
maculopathy
- anti-VEGF
non-proliferative
- observation / panretinal laser photocoagulation
Proliferative
- panretinal laser photocoagulation
- anti-VEGF
Vitreous haemorrhage
- vitreoretinal surgery
What might you see on fundoscopy with diabetic retinopathy?
Blot haemorrhages
Hard exudates
Microaneurysms
Venous beading
Cotton wool spots
Intraretinal microvascular abnormalities
Neovascularisation
Complications of diabetic retinopathy?
Retinal detachment
Vitreous haemorrhage
Rebeosis iridis - new blood vessel formation in iris
Optic neuropathy
Cataracts
Hypertensive retinopathy
damage to small blood vessels in retina from systemic HTN
Hypertensive retinopathy Px
- can be asym
- double vision / blurred vision / reduced acuity / visual field defects
- headaches
- eye pain
- N+V
- end organ damage - HF, AKI, chest pain
Hypertensive retinopathy Ix
- BP
- fundoscopy
- OCT / fluorescein angiography
What might you see on hypertensive retinopathy fundoscopy?
- silver / copper wiring
- AV nipping
- cotton wool spots
- hard exudates
- retinal haemorrhages
- papilloedema
Hypertensive retinopathy - Keith-Wagener classification
Stage 1: Mild narrowing of the arterioles
Stage 2: Focal constriction of blood vessels and AV nicking
Stage 3: Cotton-wool patches, exudates and haemorrhages
Stage 4: Papilloedema
Hypertensive retinopathy Mx
- control BP
- stop smoking
- control lipids
What are cataracts? What are possible causes?
opacification of lens causing reduced visual acuity
Causes
smoking, alcohol, age, trauma, DM, long-term steroids, radiation, myotonic dystrophy, hypocalcaemia
Cataracts Px
- gradual onset, asymmetrical
- blurry vision
- faded colour vision
- starbursts around lights - at night
- poor night vision
- white/brown lens when light shone on eye
- reduced red reflex
Cataracts Ix
- ophthalmoscopy - normal fundus / optic nerve
- slit lamp
Cataracts Mx
- surgery
- stronger glasses, brighter lights in meantime
key examination finding in cataracts?
loss of red reflex
lens may appear grey / white
name 1 rare but serious complication of cataract surgery?
Endophthalmitis: inflammation of the inner contents of the eye (usually due to infection)
Tx with intravitreal antibiotics injected directly into eye
Blepharitis - causes, Px and Mx
- inflammation of eyelid margins
Causes
- meibomian gland dysfunction - lack of oil, drying of eyes
- seborrhoeic dermatitis / staph infection
Px
- bilateral
- gritty, sticky eyes
- red eyelid margins
- swollen - staph
Mx
- hot compress
- lid hygiene - cotton wool buds, warm water, baby shampoo
- artificial tears - dry eyes
Stye - types, Px and Mx
- painful red lump on eyelid edge
- infection and inflammation of tear glands
Types
External - infection of glands of zeis / moll
Internal - infection of meibomian glands
Px
external - tender red lump along eyelid +/- pus
internal - deeper, more painful, may point inwards
Mx
- hot compress
- analgesia
- topical abx if conjunctivitis
Chalazion - Px and Mx
- obstruction of sebaceous gland causing gland to enlarge
- it can rupture, prompting inflammatory response
Px
- swelling in eyelid
- may be painless / tender
- red
Mx
- hot compress
- analgesia
- topical abx if inflamed
- surgical drainage if the above fails
Entropion
- eyelid turns in
Mx
- tape eyelid down, eye drops to prevent eye drying
- surgery - definitive
- same day ophthal referral if risk to sight
Ectropion
- eyelid turns out, usually bottom
Mx
- mild - no tx
- eye drops
- surgery
- same day ophthal referral if risk to sight
Trichiasis : Px and Mx
- inward growth of eyelash
Px
- painful
- red, watery eye
- feels like FB in eye
Mx
- remove eyelash
- electrolysis, cryotherapy, laser tx if recurrent growth
- same day referral if risk to sight
What might cause an abnormal pupil shape?
- trauma, eg cataracts surgery
- anterior uveitis - adhesions
- AACG - vertical oval shape
- rubeosis iridis - neovascularisation of iris
- coloboma - congenital malformation
- tadpole pupil - spasm in iris - migraines
what might cause mydriasis (dilated pupil)
- 3rd nerve palsy
- Homes-Adie syndrome
- raised ICP
- congenital
- trauma
- phaeochromocytoma
- drugs - atropine, cocaine, amphetamines, TCAs
what might cause miosis (constricted pupil)
- Horner syndrome
- cluster headaches
- Argyll-Robertson pupil
- opiates
- nicotine
- pilocarpine
3rd nerve palsy - Px and possible causes ?
- ptosis
- dilated pupil
- divergent strabismus - down + out eye
Causes
- idiopathic
With sparing of pupil (microvascular - psym fibres spared):
- DM, HTN, ischaemia
Full palsy - compression
- tumour, trauma, cavernous sinus thrombosis, PCA aneurysm, raised ICP
CN4 palsy Px
eye ‘up and out’ when looking forward
CN6 palsy Px
right eye turns ‘in’ on looking forward
innervation of ocular muscles
LN6(SO4)3 - mnemonic
What is Horner’s?
- damage to sympathetic nerves system supplying face
- sympathetic nerves arise from spinal cord in chest (preganglionic nerves)
- enter sympathetic ganglion inneck and exist as post ganglionic nerves
- post ganglionic nerves travel to head alongside internal carotid
Ix
- Cocaine eye drops? - cause dilatation in normal eye, not in Horner’s
- adrenaline eye drops - as above
locating Horner’s?
Determined by the anhidrosis (loss of sweating)
- Central lesions (occurring before the nerves exit the spinal cord) cause anhidrosis of the arm, trunk and face
- Pre-ganglionic lesions cause anhidrosis of the face. - - Post-ganglionic lesions do not cause anhidrosis.
what is the Horner’s syndrome triad?
- ptosis
- miosis
- anhidrosis